This proposal requests funds to purchase a mini-supercomputer that will provide an highly cost effective solution to the problem of carrying out large scale computations of direct relevance to a number of N.I.H. funded research projects at the University of Pennsylvania. The group of researchers in question (Klein, Blasie. Hochstrasser, Lu, and Opella) is currently studying structural and dynamical behavior in problems ranging from micelles and membranes to proteins and genes using a variety of theoretical and experimental techniques. Computer simulation molecular dynamics calculations (Klein)have now emerged as a powerful complement to real experiments such as X-ray and neutron scattering (Blasie), NMR (Opella/Lu), and laser light scattering (Hochstrasser) that are currently underway at Penn. to probe biophysical systems. Specifically the requested mini-supercomputer will be used to carry out molecular dynamics simulations in order to aid the interpretation of experiments relating to: a) micelles and bilayers in aqueous solution (Klein), b) model membrane systems i.e. substrate supported monolayers and bilayers (Klein/Blasie), c) protein structure refinement constrained via NMR data (Opella), d) protein and nucleic acid structure refinement constrained via NMR data (Lu), and e) molecular motions in liquids and proteins (Hochstrasser). The long term goal of the above program is to provide a strong link between theory and experiment not only in order to better interpret experimental data but also to suggest new experiments that might thereby resolve outstanding issues of interpretation.